This study investigates the hypothesis that alcoholics have a high incidence of neurophysiological anomalies akin to those found in endogenous affective disorders. The hypothesis derives from the converging findings of family- genetic and pharmacological studies of alcoholics. Family genetic studies indicate a very high incidence of unipolar depression among the first degree female relatives of alcoholics. Recent pharmacological studies of detoxified alcoholics show a favorable treatment response to drug types and/or dosage levels most specific to the treatment of endogenous affective disorders. The relatively distinctive visual evoked potential (VEP) patterns of unipolar depressives, bipolar affectives and normal controls provide an additional means for testing the hypothesis that many alcoholics may have a predisposition to affective disorders, which is masked by alcohol abuse. Confirmations of the hypothesis could have significant treatment and preventive implications. It could suggest the optimal treatment for alcoholics with the neurophysiological anomaly and identify individuals at especially high risk for alcohol or depression within the families of alcoholics.